net: Add NET_API to url_request.

net/http/http_transaction_factory.h

Index: net/http/http_transaction_factory.h
===================================================================
--- net/http/http_transaction_factory.h	(revision 85994)
+++ net/http/http_transaction_factory.h	(working copy)
@@ -7,6 +7,7 @@
 #pragma once
 
 #include "base/memory/scoped_ptr.h"
+#include "net/base/net_api.h"
 
 namespace net {
 
@@ -16,7 +17,7 @@
 
 
 // An interface to a class that can create HttpTransaction objects.
-class HttpTransactionFactory {
+class NET_API HttpTransactionFactory {
  public:
   virtual ~HttpTransactionFactory() {}